The present invention relates to the manufacture of automatic machines for packaging different kinds of articles in pieces of sealed blister band, commonly called blister packs. In particular, these articles of different kinds include pharmaceuticals such as capsules, tablets, pills and so on.
There are known machines for making blisters in a heat-formable band which are then filled with the articles being packed, sealed and then severed into blister packs.
The blister band, after filling, is driven through a station for checking the presence of the articles in the blisters (this station being possibly equipped also with means capable of detecting the integrity of the articles), a station in which an aluminium sealing film is applied to the side of the blister band in which the blisters are open, a severing station in which the blister band already sealed is cut in single blister packs.
In the sealing film applying station, the aluminium film is unrolled from a reel located nearby. Recently, automatic packaging machines have been designed with the possibility of carrying a plurality of aluminium film reels. The reels are set before starting the machine and then automatically spliced during operation, each one to the previous one being running out.
For these machines, there is the need to perform a size change-over, that means adjusting all the operative units to different sizes of the blister packs being produced, in a time as short as possible. It is also preferable to decrease the number of operators necessary to perform the change-over operation, however keeping the time necessary as short as possible.
Machines and methods known so far require, on the contrary, long time operations to release the operative units, that are fastened to the related carriers joined to the machine frame, to replace and/or adjust the position of the operative units, and lastly to lock again the units.
In particular, it is necessary to centre the sealing film supply device with respect to the blister band to be sealed. The centring operation is to be performed each time the width of the blister band changes.
The only two possibilities, therefore, include either having more people make the change-over/adjustment or planning a longer time before restoring normal operation.
Also replacement of the running out reels of film requires an operator, and therefore it increases the production costs of the whole machine. In particular, this is a big problem when, due to unavoidably short duration of the reels, the operator has to intervene each time that a reel is becoming empty to replace it with a full reel, before the reel is actually empty.
An example of a structure similar to the one used to solve the above mentioned problem of the packaging machines, can be found in the publication EP-A-0378874, which relates to a method for feeding band material to a copying machine.
The method is carried out by a machine equipped with a rotating drum with situated thereon four reels of band of different sizes. When it is necessary to change the size of the material to be supplied, the drum is rotated until the desired reel is brought near the taking out station. The drum carries also, near each reel, two motorised rollers, between which the band material ready to be taken is situated.
The publication DE-A-3933214 relates to a packaging machine provided with more film reels.
For each film reel there are two rollers, one of which driven by motor means to convey the film, while the other pushes the film against the driven roller. The conveying rollers are in gear engagement.
According to the publication GB-A-2135282, there is a star-like reel carrier for carrying three film reels.
Before the splicing operation, the replacement reel is moved from a first station to a second station, where a clip holding the beginning of the film is removed by a moving element and transferred to the splicing station.
When the reel in the third station is running out, the film is spliced with the film from the new reel in the splicing station. Then, the run out reel is brought back to the first station to be replaced.
An object of the present invention is to provide an apparatus that allows to perform size change over operations in extremely reduced time, without intervention of more than one operator.
Another object of the present invention is to allow repetitive replacement of the running out reel with a full reel without the operator""s intervention after each splicing, so as to reduce time necessary for the preparation of the replacement reels at the beginning of each working turn, so that only one intervention, for starting the machine, by only one operator, is sufficient.
Further object of the present invention derives from what has been said above, i.e. to provide an apparatus that allows an easy and rapid substitution of run out reels with new reels, thus facilitating the operator""s intervention.
Still further object of the present invention is to provide an apparatus that can be automatically set and adjusted in relation to the size of the blister band to be sealed, and consequently of the film, so that the operator does not have to perform long adjustment operations.
Finally, it is an object of the present invention to provide an apparatus capable to automatically control and correct the course of the film to be applied on the blister band to make up for its possible offset.
The above mentioned objects are obtained by means of an apparatus for supplying sealing film for a blister band to a splicing station including:
a drum rotating about a horizontal axle and featuring a plurality of carriers for receiving reels of films;
a station for splicing the film coming from a running out reel, situated in an unrolling position, with a film to be spliced coming from a new reel;
means for preparing the leader end of the film coming from the replacement reel in the region of the splicing station;
means allowing and determining a rotation of the drum about a vertical axis, means for automatic adjustment of the axial movement of the drum carrier axis upon the size change of the blister band to be closed with said film, and means for control and automatic adjustment of lateral offset of the sealing film.
Other constructive aspects of the subject apparatus are described in the sub-claims.